GeoJsonContent overrides fillParserOutput which was deprecated in MediaWiki 1.38

[samwilson]

Setup

• Maps version: 3310ae98c33eeaee4a5ce2ac615b0810bb31ab05
• MW version: fa8646ca7ba3bb599154f02d1793c8c6c99b0875
• PHP version: 8.1.2

Issue

Saving a new GeoJSON page results in a deprecation notice on Mediawiki 1.39:

Deprecated: Maps\GeoJsonPages\GeoJsonContent overrides fillParserOutput which was deprecated in MediaWiki 1.38. [Called from MediaWiki\Content\Renderer\ContentRenderer::getParserOutput in mediawiki/includes/content/Renderer/ContentRenderer.php at line 47] in mediawiki/includes/debug/MWDebug.php on line 381

Steps to reproduce the observation (recommendation is to use the sandbox):

1. Enter GeoJSON into a new GeoJson page.
2. Save that page.
3. Observe the above deprecation notice.